Composite Solid Electrolyte Coating for Low-Resistance Ion Transport
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Solution Overview
Problem
Conventional liquid electrolytes are volatile, prone to leakage, and unstable at high temperatures, while solid electrolytes have high electrical resistance, affecting ion conductivity in batteries.
Innovation Solution
A composite solid electrolyte comprising lithium lanthanum zirconium oxide particles with a protective layer of lithium phosphate, and optionally a fluorine-containing colloid, to enhance ion conductivity and reduce electrical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solid electrolyte is used to replace liquid electrolyte, then stability is improved, but electrical resistance increases
Solution Approach 1:
The patent uses composite solid electrolyte materials combining lithium lanthanum zirconium oxide (LLZO) with lithium phosphate protective layers and fluorine-containing colloids to achieve both high stability and low electrical resistance. The composite structure allows the LLZO core to provide structural stability while the protective layers and colloid matrix reduce interfacial resistance and improve ion transport.
Solution Approach 2:
The patent optimizes particle size parameters of LLZO to 50-500 nm range and controls the thickness of protective layers to 30-45 nm, along with adjusting the weight ratios of components (LLZO: lithium phosphate from 2:1 to 3:1, LLZO: fluorine-containing polyolefin from 30% to 50%). These parameter optimizations balance the stability and electrical resistance properties.
2Reliability
If particle size of lithium lanthanum zirconium oxide is reduced, then ion conductivity is improved, but manufacturing precision becomes more difficult
Solution Approach 1:
The patent specifies a particle size range of 50-500 nm for LLZO particles, which is optimized to provide sufficient surface area for ion conductivity while remaining manufacturable. This parameter range balances the need for small particles (for conductivity) with practical manufacturing constraints.
Solution Approach 2:
The patent introduces protective layers of lithium phosphate and fluorine-containing colloids as intermediary substances that coat the LLZO particles. These intermediaries protect the nanoparticle surfaces during handling and manufacturing processes, reducing aggregation and making it easier to maintain precise particle size distributions.
3Reliability
If protective layer is added to lithium lanthanum zirconium oxide particle, then stability is improved, but device complexity increases
Solution Approach 1:
The protective layer is not an additional separate component but is integrated into a composite material system where lithium phosphate forms a coating on LLZO particles that are then dispersed in fluorine-containing colloid matrices. This composite approach provides stability while maintaining a relatively simple overall structure suitable for battery applications.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The composite solid electrolyte achieves high ion conductivity, mechanical strength, stability, and low electrical resistance, maintaining performance over long-term use and increasing battery cycle numbers.
Implementation Method 1
The lithium lanthanum zirconium oxide particle is mixed with phosphoric acid to form a protective layer containing lithium phosphate covering an outer surface of the lithium lanthanum zirconium oxide particle by an acid-base reaction
Data Source
AI summary
The present disclosure provides a composite solid electrolyte. The composite solid electrolyte includes a lithium lanthanum zirconium oxide particle and a protective layer containing lithium phosphate. An average particle size of the lithium lanthanum zirconium oxide particle is smaller than 500 nm and larger than 50 nm. The protective layer containing lithium phosphate covers an outer surface of the lithium lanthanum zirconium oxide particle.